This invention relates to filter cigarettes. More particularly, the present invention relates to filter cigarettes which are adjustable by the smoker to vary the air dilution value.
It is known to produce variable dilution cigarettes having integral rotatable elements for controlling dilution. The rotatable element can be a rotatable band of tipping paper retained by stationary bands against axial displacement and having a slit overlying a slit in the filter plug wrap with which it can be rotated into and out of registry. Alternatively, it can be a rotatable section of the filter plug, carrying with it a section of tipping paper extending over a stationary section of the filter plug. The extending section of the tipping paper has a slit which overlies a slit in the plug wrap on the stationary filter plug segment. The slits can be moved in and out of registry by rotating the rotatable filter segment. Such a cigarette is described in commonly-assigned U.S. Pat. No. 4,532,943, which is hereby incorporated by reference in its entirety.
In the manufacture of these types of cigarettes, the slits in the tipping paper and plug wrap are most easily formed by simultaneously slitting both layers with a knife or laser beam. The cigarettes are therefore assembled initially with the slits fully in registry both longitudinally and rotationally. The dilution level can then be adjusted by rotating the rotatable segment varying the rotational registry of the slits.
In such a cigarette, if the rotatable filter segment is rotated too far, it may break off. In addition, depending on the placement of the dilution slits, once the rotatable segment is rotated to an extreme of dilution, continued rotation of the rotatable filter segment in the same direction will begin to adjust the dilution level back toward the other extreme. These results of over-rotation might not be expected by a smoker, who may instead expect that continued rotation in a given direction would continue to adjust the dilution level in the same direction.
Such cigarettes, if manufactured by conventional cigarette making machinery, would always come from the pack set to the same dilution level. If a tactile indication of the rotational position of the rotatable segment were provided, a smoker who was familiar with the cigarette brand would be able to adjust the cigarette to a desired dilution level without looking--e.g., at night.
It would be desirable to be able to provide a variable dilution cigarette of the type described above which could not be rotated out of a preset rotational range and which provided a tactile indication of its rotational position.